The invention relates to aqueous correction fluids.
Correction fluids are used for obscuring handwritten, typewritten, photocopied, or laser printed markings on paper. Generally, a correction fluid is applied, in liquid form, to a marking on a paper surface, and then allowed to dry to form a film which effectively covers the underlying marking and is capable of receiving a corrective marking.
Water-based correction fluids typically include a pigment, e.g., titanium dioxide, and a latex binder which is usually an aqueous polymer emulsion, e.g., an acrylic copolymer or ethylene vinyl acetate (EVA) emulsion. While water-based fluids are better for the environment than solvent based systems, the water and/or any organic solvents formulated into aqueous based correction fluids have a tendency to dissolve or solubilize the dyes present in the underlying marking, causing "bleeding" or "smudging" of the underlying ink marking into the liquid correction fluid, which results in a discoloration of the dried film. The latex binder can, in some formulations, reduce the dissolution of underlying markings to which the fluid is applied, but they often do not prevent the problem of bleeding or smudging entirely. "Non-water-fast" inks, e.g., porous or rollerball pen inks, are especially difficult to cover with aqueous correction fluids without bleeding of the marking into the correction fluid.